Ocular surface interferometery (OSI) devices and systems for imaging, processing, and/or displaying an ocular tear film

• US 8,746,883 B2
• Filed: 04/01/2010
• Issued: 06/10/2014
• Est. Priority Date: 04/01/2009
• Status: Active Grant

• Current Assignee: TearScience Inc. (Johnson & Johnson)
• Original Assignee: TearScience Inc. (Johnson & Johnson)
• Inventors: Korb, Donald R., Weber, William L., Chinnock, Randal B., Gravely, Benjamin T., Grenon, Stephen M.
• Primary Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US12/798,275
• Publication Number:
  US 20100253907A1
• Time in Patent Office: 1,531 Days
• Field of Search: 351/206, 351/200, 351/205, 351/209, 351/210, 351/221, 351/222, 351/223, 351/245, 351/246, 351/212, 351/208, 351/160.R, 351/159, 351/247, 600/356, 600/346, 600/476, 600/425
• US Class Current: 351/206
• CPC Class Codes: A61B 3/0025 characterised by electronic signal processing, e.g. eye models
• CPC Class Codes: A61B 3/0041 characterised by display arrangements
• CPC Class Codes: A61B 3/1005 for measuring distances inside the eye, e.g. thickness of the cornea A61B3/11 takes precedence
• CPC Class Codes: A61B 3/101 for examining the tear film
• CPC Class Codes: A61B 3/14 Arrangements specially adapted for eye photography apparatus or arrangements for taking photographs per se G03B
• CPC Class Codes: G06T 2207/30041 Eye; Retina; Ophthalmic
• CPC Class Codes: G06T 7/0012 Biomedical image inspection

Abstract

Ocular surface interferometry (OSI) devices, systems, and methods are disclosed for measuring a tear film layer thickness (TFLT) of the ocular tear film, including lipid layer thickness (LLT) and/or aqueous layer thickness (ALT). The measured TFLT can be used to diagnosis dry eye syndrome (DES). In certain disclosed embodiments, a multi-wavelength light source can be controlled to illuminate the ocular tear film. Light emitted from the multi-wavelength light source undergoes optical wave interference interactions in the tear film. An imaging device can be focused on the lipid layer of the tear film to capture optical wave interference interactions of specularly reflected light from the tear film combined with a background signal(s) in a first image. The imaging device can also be focused on the lipid layer of the tear film to capture a second image containing the background signal(s) present in the first image. The second image can be subtracted from the first image to reduce and/or eliminate the background signal(s) in the first image to produce a resulting image. The resulting image can be processed and analyzed to measure a tear film layer thickness (TFLT), including lipid layer thickness (LLT) and/or aqueous layer thickness (ALT).

Claims

1. An apparatus for imaging an ocular tear film, comprising:

a control system configured to;

(a) receive at least one first image containing optical wave interference of specularly reflected light and a background signal from a region of interest of an ocular tear film captured by an imaging device while illuminated by a multi-wavelength light source;

(b) receive at least one second image containing only the background signal from the region of interest of the ocular tear film captured by the imaging device; and

(c) subtract the at least one second image from the at least one first image to generate at least one resulting image containing the optical wave interference of the specularly reflected light from the region of interest of the ocular tear film with the background signal removed or reduced.

2. The apparatus of claim 1, wherein the optical wave interference of the specularly reflected light from the ocular tear film is comprised of one or more optical wave interference signals.

3. The apparatus of claim 1, wherein the background signal includes at least one of stray light and ambient light.

4. The apparatus of claim 1, wherein the imaging device is configured to capture the at least one second image when the multi-wavelength light source is not illuminating the region of interest of the ocular tear film.

5. The apparatus of claim 1, wherein the imaging device is configured to capture the at least one second image when the multi-wavelength light source is illuminating the region of interest of the ocular tear film.

6. The apparatus of claim 5, wherein the background signal includes diffusely reflected light resulting from illumination of the ocular tear film.

7. The apparatus of claim 6, wherein the background signal includes the diffusely reflected light from an iris of an eye.

8. The apparatus of claim 5, wherein the imaging device is configured to not capture the specularly reflected light from the region of interest of the ocular tear film when capturing the background signal from the region of interest of the ocular tear film in the at least one second image.

9. The apparatus of claim 1, wherein the control system is further configured to control the multi-wavelength light source to produce the specularly reflected light from at least one first portion of the region of interest of the ocular tear film while the multi-wavelength light source obliquely illuminates at least one second portion of the region of interest of the ocular tear film adjacent to the at least one first portion.

10. The apparatus of claim 9, wherein the control system is further configured to control the multi-wavelength light source to produce the specularly reflected light from the at least one second portion of the region of interest of the ocular tear film while the multi-wavelength light source obliquely illuminates the at least one first portion of the region of interest of the ocular tear film adjacent to the at least one second portion.

11. The apparatus of claim 10, wherein the control system is configured to receive the at least one first image containing the optical wave interference of the specularly reflected light and the background signal by being configured to:

capture a first tiled pattern of the specularly reflected light including the background signal from the at least one first portion of the region of interest of the ocular tear film in the at least one first image by the imaging device; and

capture a second tiled pattern of the specularly reflected light including the background signal from the at least one second portion of the region of interest of the ocular tear film in the at least one second image by the imaging device.

12. The apparatus of claim 11, wherein the control system is configured to receive only the at least one second image containing the background signal from the region of interest of the ocular tear film captured by the imaging device by being configured to:

capture the background signal from the at least one second portion of the region of interest in the first tiled pattern in the at least one first image; and

capture the background signal from the least one first portion of the region of interest in the second tiled pattern in the at least one second image.

13. The apparatus of claim 12, wherein the at least one first portion and the at least one second portion are located adjacent to each other.

14. The apparatus of claim 12, wherein the control system is further configured to combine the at least one first image to the at least one second image to form the at least one resulting image in a tiled pattern containing the optical wave interference of the specularly reflected light from the region of interest of the ocular tear film with the background signal removed or reduced.

15. The apparatus of claim 11, wherein the first tiled pattern is comprised from the group consisting of a teeth pattern and a plurality of concentric patterns.

16. The apparatus of claim 11, wherein the at least one first portion and the at least one second portion are comprised of equal or approximately equal areas.

17. The apparatus of claim 1, wherein the control system is further configured to sequentially control the imaging device to capture the optical wave interference of the specularly reflected light and the background signal in the at least one first image to provide a plurality of first images, and capture the background signal in the at least one second image to provide a plurality of second images interleaved with the plurality of first images to provide a plurality of first and second image pairs.

18. The apparatus of claim 17, wherein the control system is configured to subtract the plurality of second images from the plurality of first and second image pairs from corresponding first images from the plurality of first and second image pairs to generate a plurality of resulting images each containing the optical wave interference of the specularly reflected light from the region of interest of the ocular tear film with the background signal removed or reduced.

19. The apparatus of claim 1, wherein the control system is further configured to set a linear response on the imaging device.

20. The apparatus of claim 19, wherein the control system is further configured to set the linear response by being configured to adjust a gamma correction of the imaging device.

21. The apparatus of claim 1, wherein the control system is further configured to synchronize illumination of the region of interest of the ocular tear film by the multi-wavelength light source with the at least one first image.

22. The apparatus of claim 1, wherein the control system is further configured to selectively control one or more light emissions devices within the multi-wavelength light source when illuminating the region of interest of the ocular tear film.

23. The apparatus of claim 1, wherein the control system is further configured to position at least one of the multi-wavelength light source and the imaging device relevant to the ocular tear film prior to capture of the at least one first image and capture of the at least one second image.

24. The apparatus of claim 1, further comprising the multi-wavelength light source configured to illuminate the region of interest of the ocular tear film with multi-wavelength light.

25. The apparatus of claim 24, wherein the multi-wavelength light source is comprised of a multi-wavelength Lambertian light source configured to uniformly or substantially uniformly illuminate the region of interest of the ocular tear film.

26. The apparatus of claim 1, further comprising the imaging device configured to capture the optical wave interference of the specularly reflected light and the background signal from the region of interest of the ocular tear film while illuminated by the multi-wavelength light in the at least one first image, and capture the background signal from the region of interest of the ocular tear film in the at least one second image.

27. The apparatus of claim 1, wherein the control system is further configured to display at least one of the at least one first image, the at least one second image, or the at least one resulting image on a visual display.

28. The apparatus of claim 27, wherein the control system is further configured to adjust a linearity of the at least one resulting image before displaying the at least one resulting image on the visual display.

29. The apparatus of claim 1, wherein the control system is further configured to display the at least one resulting image overlaid onto at least one of the at least one first image and the at least one second image on a visual display.

30. The apparatus of claim 27, wherein the control system is further configured to adjust either a contrast level, a saturation level, or both the contrast level and the saturation level of the at least one resulting image displayed on the visual display.

31. The apparatus of claim 13, wherein the at least one first portion is comprised of a plurality of first portions of the region of interest, and the at least one second portion is comprised of a plurality of second portions of the region of interest.